Thursday 16 December 2010 17.19 EST
First published on Thursday 16 December 2010 17.19 EST

It was just a day after the 30th anniversary of John Lennon's death that Nick Clegg, seemingly without a flicker of irony, chose to denounce those protesting against a rise in university tuition fees as "dreamers". Well, he may say so, but I'm sure they're not the only ones. It got me to thinking about dreamers and their songs, from Lennon's Imagine, to the Staple Singers' Respect Yourself, via Joan Baez, Bob Dylan, Billy Bragg. It is my fervent hope, in these politically distasteful times, that the songs of the protesters, the songs of the dreamers, might enjoy something of a renaissance.

For the last couple of years, Britain's principal musical protest has been in the form of revisiting old songs in the hope of stalling the X Factor juggernaut – last Christmas of course it was Rage Against the Machine's Killing in the Name keeping Joe McElderry off the top of the charts; this year – as pondered by my Film&Music colleague Tom Ewing, we have Cage Against the Machine, a rather wonderful plot to keep Matt Cardle's cover of a Biffy Clyro hit away from the top spot by encouraging us to buy John Cage's 1952 avant-garde composition 4'33" – a song in which the players are instructed not to play at all. Now some 87,000-strong on Facebook, the campaign's mission statement is simple: "Together," its masterminds insist, "we can make it a silent night on Radio 1."

Cage was a dreamer, but 4'33" is not really silent, nor is it really a protest song. Rather, it was one of Cage's explorations of the "activity" of sound, the culmination of an idea he first mentioned in a lecture at Vassar college in the late 1940s, speaking of a desire to compose "a piece of uninterrupted silence and sell it to Muzak Co. It will be three or four-and-a-half minutes long – those being the standard lengths of 'canned' music … It will open with a single idea which I will attempt to make as seductive as the colour and shape and fragrance of a flower. The ending will approach imperceptibly."

Crucially, Cage was inspired by the work of his friend, the artist Robert Rauschenberg, who in 1951 had produced White Paintings, a series of seemingly blank canvasses (though in truth they were painted with white house paint). The idea was that the canvasses would change colour according to differing light conditions wherever they happened to hang, their appearance shifting to reflect the time of day, say, or the shape of the exhibition space, or even the number of people in the room.

Cage described these canvasses as "airports of the lights, shadows and particles", and the following year he created 4'33", an aural equivalent. Though it is, in many respects, a soundless composition, Cage's intention was that 4'33" would similarly reflect the ambient sounds of wherever it was performed – the musicians, the room, the audience. After all, as Cage put it: "Everything we do is music."

This is, in many ways, how we hear all songs; 4'33" is simply the rawest example. The light, literal and metaphorical, affects the way that music falls on our ears; we hear a song differently indoors to outdoors, alone or in company, sitting still to when we are in motion. The aural canvas appears a different colour when we are in love, when we are in despair, when we have painted it with the layers of our emotional lives.

Cage once spoke of his experience of visiting an anechoic chamber and finding himself startled to hear not silence but two distinct sounds: "one high, my nervous system in operation, one low, my blood in circulation". Even without intention, he found, we are contributing to the music.

And I think there is something rather beautiful in the idea that if those silent four minutes and 33 seconds come to be played on Radio 1 this Christmas, we will each hear it quite differently; not a silent night at all, but a musical blank canvas coloured by the sound of our own blood pumping, by the lights, shadows and particles of our lives.